Biotinidase Deficiency

BTD is extracted from filter paper using a special buffer containing biotinyl-6-aminoquinoline (B-6-AQ). In the process, BTD converts B-6-AQ into biotin and 6-aminoquinoline (6-AQ). The 6-AQ naturally fluorescence is directly linked to the BTD activity in the sample.

Biotin (also known as vitamin H or B8) is an essential vitamin belonging to the vitamin B complex. Biotin functions as a coenzyme essential for the proper functioning of gluconeogenesis, fatty acid synthesis and catabolism of various branched chain amino acids.

Biotinidase deficiency is a congenital error in biotin recycling metabolism. 

A deep biotinidase deficiency is defined as a residual activity < 10% of normal mean serum biotinidase activity, while a partial deficiency is defined as a residual activity between 10% and 30% of normal mean activity.

Young children with a profound biotinidase deficiency diagnosis usually develop symptoms of severe neurological abnormalities including convulsions, hypotonia, ataxia, psychomotor retardation, optic atrophy, sensorineural deafness and skin disorders. Later, weakness of the motor limbs and spastic paresis also develop. 

Individuals with partial biotinidase deficiency may suffer from symptoms of hypotonia, skin rashes and hair loss, particularly during periods of stress such as a prolonged infection.

The treatment consists of daily vitamin supplements of biotin taken by mouth. This treatment is remarkably effective if started at a very early age.